Particle accelerators generally are grouped into different categories according to their fundamental concepts:    1) Those that use constant electrostatic fields such as Van de Graaff accelerators;    2) Those that make use of radiofrequency cavities in a straight line such as linear accelerators;    3) Those that use the electric fields induced by a time varying magnetic field to accelerate a particle such as the betatron; and    4) Circular accelerators that recirculate the beam of particles through a radiofrequency cavity to reach a desired energy such as a cyclotron, synchrotron, microtron, racetrack microtron or Rhodotron™.
Different names have been used to describe different combinations of the ideas represented by these categories and the concepts they represent, as they have been perceived to be advantageous in different applications. Many are discussed in books about accelerator design such as M. S. Livingston and J. P. Blewett, “Particle Accelerators”, McGraw Hill Book Company, Inc., New York, 1962. They all apply the fundamental Maxwell equations and particle dynamics in magnetic and electric fields to accelerate particles and to form accelerated beams.
A novel configuration for a particle beam accelerator is described in pending U.S. patent application Ser. No. 12/351,234, “Methods And Systems For Accelerating Particles Using Induction To Generate An Electric Field With A Localized Curl,” by William Bertozzi, Stephen E. Korbly and Robert J. Ledoux. The accelerator may have a vacuum chamber that is annular or toroidal in shape and which serves as the accelerator beamline. The beamline has an electrically conductive part and an electrically non-conductive part that serves as an acceleration gap. A magnetic field that is present in the region of the vacuum chamber controls the motion of the beam within the vacuum chamber. The accelerator has two very distinct electromagnetic field regions. One is inside the vacuum chamber/beamline where the only fields other than the magnetic guide fields are those created by the accelerating potential in the region of the non-conducting acceleration gap and those induced by the beam charge on the inner walls of the conductive portion of the vacuum chamber/beamline. The other electromagnetic field region is outside the vacuum chamber/beamline where an exciting current travels along the outside surface of the conductive portion of the vacuum chamber/beamline. These two regions are coupled only via the non-conducting acceleration gap. This accelerator will hereinafter be referred to as a “localized curl accelerator.”
Most particle accelerators having a degree of complexity require methods and systems for monitoring and controlling the beams they produce. Such systems are often referred to as diagnostic systems or simply “diagnostics” and such controlling systems are often referred to as “controls”.
Pending U.S. patent application Ser. No. 12/351,241, “Diagnostic Methods And Apparatus For An Accelerator Using Induction To Generate An Electric Field With A Localized Curl,” by William Bertozzi and Robert J. Ledoux, describes methods and systems, including various beam-condition sensors, for use with a localized curl accelerator to provide essential data for beam evaluation and control. Certain of these methods and systems may also be applied in other types of accelerators.
In the case of the localized curl accelerator and associated diagnostics and/or sensors the specific characteristics of the accelerator introduces unique requirements for the processes of monitoring and controlling the beam that may be met by employing the exemplary diagnostics and/or sensors described therein and by employing the methods disclosed herein. Certain of these methods also are suitable for use with other accelerator types.